Asymmetric Catalytic Alkynylation of Acetaldehyde: Application to the Synthesis of (+)-Tetrahydropyrenophorol
作者:Barry M. Trost、Adrien Quintard
DOI:10.1002/anie.201203035
日期:2012.7.2
In control: By controlling the kinetics of alkynylation over aldolization, the challenging asymmetriccatalyticalkynylation of acetaldehyde has been realized. The resulting products are attractive synthons which are produced with good to excellent enantiocontrol, and show broad tolerance and applicability, as demonstrated by the synthesis (+)‐tetrahydropyrenophorol.
Substitution of secondary allylic phosphates with the anions derived from Ar2CH2 with BuLi or LDA proceeded regioselectively and stereoselectively without a metal catalyst, affording inversion products in good yield. Similarly,...
A biosynthetically inspired synthesis of (−)-berkelic acid and analogs
作者:Christopher F. Bender、Christopher L. Paradise、Vincent M. Lynch、Francis K. Yoshimoto、Jef K. De Brabander
DOI:10.1016/j.tet.2018.01.021
日期:2018.3
cycloaddition to deliver the tetracyclic core of berkelic acid. Our studies confirm that the original assigned berkelic acid structure is not stable and equilibrates into a mixture of 4 diastereomers, fully characterized by X-ray crystallography. In addition to berkelic acid, C22-epi-berkelic acid, and nor-berkelic acids, we synthesized C26-oxoberkelic acidanalogs that were evaluated against human cancer cell
The oxidoreductases Lactobacillus brevis alcohol dehydrogenase (LBADH) and Candida parapsilosis carbonyl reductase (CPCR) are suitable catalysts for the reduction of ketones to afford enantiopure sec. alcohols. A broad variety of alkynones (1, 3, and 5) are accepted as substrates and the corresponding propargylic alcohols (2, 4, and 6) are obtained in good yield and excellent enantiomeric excess. By
A Boron–Oxygen Transborylation Strategy for a Catalytic Midland Reduction
作者:Kieran Nicholson、Joanne Dunne、Peter DaBell、Alexander Beaton Garcia、Andrew D. Bage、Jamie H. Docherty、Thomas A. Hunt、Thomas Langer、Stephen P. Thomas
DOI:10.1021/acscatal.0c05168
日期:2021.2.19
The enantioselective hydroboration of ketones is a textbook reaction requiring stoichiometric amounts of an enantioenriched borane, with the Midland reduction being a seminal example. Here, a turnover strategy for asymmetric catalysis, boron–oxygen transborylation, has been developed and used to transform the stoichiometric boranereagents of the Midland reduction into catalysts. This turnover strategy